1. Field
The described technology relates generally to a rechargeable battery for controlling charging resistance of a case depending on temperature for a perforation characteristic of a conductor.
2. Description of the Related Art
Unlike a primary battery that cannot be recharged, a rechargeable battery may be repeatedly charged and discharged. A small-capacity rechargeable battery is used for small portable electronic devices such as mobile phones, notebook computers, camcorders, and the like, while a large-capacity rechargeable battery is used as a motor-driving power source for hybrid vehicles and electric vehicles.
The rechargeable battery may include an electrode assembly having a positive electrode and a negative electrode provided on either side of a separator, a case accommodating the electrode assembly, a cap plate sealing an opening of the case, and an electrode terminal penetrating the cap plate and electrically connected to the electrode assembly.
When a conductive material penetrates the case of the rechargeable battery to pierce the electrode assembly, a high-voltage current flowing through the electrode terminal flows again toward the electrode assembly through the cap plate, the case, and the conductive material. If the amount of high-voltage current is large, the electrode assembly may be ignited or explode.
When a case is charged with a positive electrode in the rechargeable battery and charging resistance for connecting a positive terminal and a cap plate at room temperature is great, a current that flows to the electrode assembly through the case and the conductor is restricted when perforating the conductor so a possibility of ignition and explosion is reduced, but the charging resistance is low so the possibility of ignition and explosion is increased.
Also, when the charging resistor for connecting the positive terminal and the cap plate becomes lower in the overcharge and high temperature condition, an external short circuit by an external short-circuit unit provided between the negative terminal and the cap plate becomes easier but it cannot reduce the predetermined charging resistor so the external short circuit becomes difficult.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.